Citation and License

Journal of Biology 2008, 7:3
doi:10.1186/jbiol62

Published: 31 January 2008

Abstract

Background

The dissection of biological pathways and of the molecular basis of disease requires
devices to analyze simultaneously a staggering number of protein isoforms in a given
cell under given conditions. Such devices face significant challenges, including the
identification of probe molecules specific for each protein isoform, protein immobilization
techniques with micrometer or submicrometer resolution, and the development of a sensing
mechanism capable of very high-density, highly multiplexed detection.

Results

We present a novel strategy that offers practical solutions to these challenges, featuring
peptide aptamers as artificial protein detectors arrayed on gold electrodes with feature
sizes one order of magnitude smaller than existing formats. We describe a method to
immobilize specific peptide aptamers on individual electrodes at the micrometer scale,
together with a robust and label-free electronic sensing system. As a proving proof
of principle experiment, we demonstrate the specific recognition of cyclin-dependent
protein kinases in whole-cell lysates using arrays of ten electrodes functionalized
with individual peptide aptamers, with no measurable cross-talk between electrodes.
The sensitivity is within the clinically relevant range and can detect proteins against
the high, whole-cell lysate background.

Conclusion

The use of peptide aptamers selected in vivo to recognize specific protein isoforms, the ability to functionalize each microelectrode
individually, the electronic nature and scalability of the label-free detection and
the scalability of the array fabrication combine to yield the potential for highly
multiplexed devices with increasingly small detection areas and higher sensitivities
that may ultimately allow the simultaneous monitoring of tens or hundreds of thousands
of protein isoforms.